Hi Phil,
Not a recommendation but this company has three offices in Sydney:
http://www.intertek.com/petroleum/testing/Looking at the addresses of this company, they appear to be co-located with the refineries.
I dare say that both Shell and Caltex have the capability to do so also.
"similar to but not diesel" in a former powerhouse.... probably 'fuel oil', a common fuel for big diesel engines.
Wikipedia has a decent section on "Fuel Oil", explaining the different grades.
T
--
Tony Brassil
Industrial Archaeologist
Heritage Consultant
ph: 0413 696 835